<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>实例</title>
<script>
    var txt="";
    function message()
    {
        try{
            adddlert("welcome guest!");
        }
        catch(err){
            txt="本页有一个错误。\n\n";
            txt+="错误描述："+err.message+"\n\n";
            txt+="点击确定继续。\n\n";
            alert(txt);
        }

    }
    </script>
    </head>
    <body>
        <input type="button" value="查看消息" onclick="message()"/>
        </body>
</html>
